I investigated FXCM offer and compared their trading conditions to ours. It turns out thet 1 lot SPX500 at FXCM equals 0.1 lot at SimpleFX. You can see it by the pip value shown in attachments. With 1 lot position at FXCM you gain/lose 10 cents per pip. With the same position size at SimpleFX you gain/lose 1 USD per pip. I marked position size, pip value and margin requirements on both screenshots. Required margin at SimpleFX is indeed about 6 USD bigger.

FXCM:



SimpleFX